Cable tension controller



' April 1942- J. STURGESS ,280,106

CABLE TENSION CONTROLLER Filed Dec. 24, 1940 2 Sheets-Sheet 2 .7 s 7 INVENTOR. JoH/v STuRssss BY Q 7 49 150 A 7' TOENEY.

man A r-.21, 1942-- UN T TATE PATIE 1 O I CABLE irffiiirflwr t: t

s John simme- Glendale; c5111., assignor to" Sturgess, Inc Los Angelesycalifl, afcorpora:

.tion of California Applicationpecember 2 device, and which cables are normally maintained under tension though subject to mucl'i greater tension whenwork is imposed upon them, par-- 'ticularly' when the work is alternately imposed on one or the other of a pair'of such cables used; to operatethe desired device back and forth as' 1 maybe desired. 1

z The principal object of the invention is to pro 1 vide an improved device which-will automaticali-l -iy maintain'the normal tension of the cables "within required limits, to compensate for expan- .means sio'n' or contraction of the structure upon which airplane, or elongation or contraction of the cables themselves from the effect of heat, stretch of the cables, wear .of idlers, etc., while at the t aforesaid purpose.

Other objects and advantages of the invention will appear in the following description and accompanying drawings:

In the drawings:

Fig. '1 is a plan view of my cable tension controlling device shown inoperative relation to a pair of control cables for maintaining them substantially at uniform tension when not under working load.

Fig. 2 is a larger scale view of the controller with the outer cover plate omitted, and portions of the frame, guides, and other parts broken away to reveal the operative relation of the parts.

Fig. 3 isan end view of Fig. 2.as seen from the right hand end thereof.

Fig. 4 is an end view of Fig. 2 as seen from the left hand end thereof.

Fig. 5 is a cross sectional view of Fig. 2 taken from the line 55 thereof.

Fig. 6 is a cross sectional view of Fig. 2 taken from the line 6--6 thereof.

Fig. 7 is a detached view of the temperature regulator indicator.

Fig. 8 is a diagrammatic drawing showing a 1 second way of equipping a pair of control cables with the device.

' the cables are used, such asthe fuselage-of an" drawings scription. to" state that the invention comprises a device having two elongated telescopicallyslidiable parts'or members-that is on member is slidable longitudinally within the other; the outer a m; seri l 151037154 I i i 13 na (01. rpm) 7 This im'rention relatesto operatinifcables,

- ropes, or wires as used to transmit mfiltiPn to a. device to be moved,' such as a rudder, aileron, or other movable part of an airplane, or any other ;-.wi11 aid; in understanding the dernemberjis arranged for anchoring to a fixed support 3 at one end for securing theends of a. pair oifcajbles to" be tensioned', in a manner so that the pulliof the cables will tend to slide the inner I member'along the outer anchored. member,- and in so'doin'g will compress a spring fulcrumed. on theouter member until'the spring balances the normal or initial pull or tension of the cables when at" rest. a The spring constantly takes up any slow tension variations in the cables caused by expansion, contraction of the cables, and/or the structureupon which they are mounted, but in event of any decided change in the pull of either cable, as when force is applied to either to accomplish some desired work movement, means a is providedfor instantly locking the inner memher tothe outer member so that no further relative sliding of the members can take place until the tension of the cablesis restored to normalcy. ."To'carryjthis outthetwo cables are attached to the' xinner sliding member through the intermedi aryfof a pivoted rocker, to the opposite ends of Y which they are linked in such a manner that upon any quick uneven pull being applied to the cables as would be occasioned by operating the rudder or other control of an air-craft, the

. cables at once operate said rocker and thereby force a pair of friction jawscarried by the inner sliding member, to grip the outer member and thus temporarily, (for the duration of theunfequal pull on the cables) lock both parts together so that during the operative pulling of either of the cables, they would both be locked off of any influence of the cable tensioning spring of the device. i

' The friction gripset up by the jaws is attained Fig. 9 is a diagrammatic drawing showing a I third way of equipping a pair of control cables with the device.

through the use of a; plurality of interleaved friction strips towhich the jaw pressure is applied, every other strip being secured at one end to'the inner sliding member, and the remaining strips at the opposite end to the outer or anchored member. I

In the drawings, the outer member comprises a pair of long channel guides I arranged in spaced relation with hollow sides confronting, and rigidly secured in such relation by a pair of transversely extending fiat arms 2, passing en: tirely across the outer edges of the channels and held in place by through bolts 3, and further send the innerjmember is provided with cured by any desired number of flat spacing bars 4 (see Fig. 1) which may be welded to the channels or held in place by short cap screws 5, and the spacers may additionally be milled out or formed with retaining grooves 6 into which the channels fit, to thus relieve the screws from excessive shear, a feature which may also apply to the flat bars 2.

Within the thus secured confronting channel guides forming the outer member, is the longitudinally slidable inner member and which comprises a yoke l which slides freelywithin the channel guides I and to the outer central end of which is pivoted a pair of flat arms I which are similar to arms 2 and likewise extend across and beyond the channels I, but instead of being secured to the channels are free for sliding along the outer sides of the channel legs while being also rockable on pivot bolt 9 which alone secures them to the yoke I. The arms 8 are preferably tied together by shouldered pins or rivets in. At the inner end of the yoke I is a transversely extending pin II which at opposite ends passes freely through holes in a plurality of thin flat metal strips l2 which extend along the space within the channel guides l and are spaced on pin II by washers l3 to provide spaces for a plurality of similar strips I which are freely interleaved with strips l2 and similarly spaced and anchored at their remote ends to the channel guides by shoulders rivets l5 passing through rectangular anchor plates l6 braced against displacement by end blocks l6 and cross strips ll secured by pins or bolts 3.

Strips l2 and M are thin, flexible and perfectly smooth on both sides, and the inner walls of the channel guides are likewise smooth, so that all of the interleaved strips are free to slide against one another and the outer ones against the channels, as the yoke is slid back and forth between the guiding channels, but if pressure were applied to force the interleaved strips in tight contact the great friction set up would at once lock the yoke against any sliding within the channels from any force within the capacity of the par- L ticular size device. To set up such pressure onthe interleaved friction strips from the relative movement of a pair of tensioned cables, I mount a rocking lever l8 transversely between the inner ends I of the yoke, on a pin [9, and at the ends of the rocker are two pairs of long links which extend along adjacent the channel guides. These links are pivotally mounted on rocking lever l8 by means of pins 2| and at their free ends they are proi vided with holes through which extend pins 22 which pivotally secure thereto the-ends 23 ofcable connections 24 of cables 25 and 26.

-Positioned between the links 20 are a pair of jaw plates or pressure plates 21 which are placed in confronting relation and at their outermost edges are in contact with the innermost of the friction strips [2, and are slightly spaced at their inner confronting edges and in contact with a pair of transversely extending pins or rollers 28, which are seated in half round sockets or bearings formed in the confronting edges of the jaw plates. These pins'28 extend beyond both sides of the jaw plates and pass through bearing apertures-in diamond shaped plates 29 disposed in contact with and on opposite sides of the jaw plates. The jaw plates are also provided with intermediately disposed holes 30 through which loosely pass a pair of pins 3| which extend through fitting apertures in both links 20. All

pins are secured from displacement by suitable cotters or heads at their ends, as indicated on some of the pins. It should be noted that with rocker l8 standing at right angles across the longitudinal center line of the device, the jaw plates will just fit between the two inner friction strips l2 but will not exert any pressure thereagainst, and so that under these conditions the inner member is free to slide back and forth within the outer member, and the interleaved strips are also freely slidable in their interleaved arrangement. However, upon moving either set of links 20 (the upper or lower set in Fig. 2 as viewed in the drawings) longitudinally with respect to the other set of links, the rocker l8 will be slightly tipped out of its normally right angle position, and in so doing will also similarly rock the diamond shaped plates 29 through their pins 3|, and by transmitting this motion to roller pins 28 will force one of the jaw plates toward one set of friction strips and the opposite plate toward the opposite set of friction strips, to thus at once set up the total friction gained through their multiple surface contact and thereby lock the inner member from any sliding within the outer member. It will be understood that since the members substantially fitin their free position, such rocking movement of rocker I; and diamond plates 2% is very slight indeed as the total clear- .ance involved between all of the plates is only suflicient to permit them to have free movement when the rocker I8 is in its right angle position with respect to the longitudinal center line of the device. As soon as the right angle position of the rocker I8 is restored, the frictional grip of the interleaved plates at once ceases and the inner. member is again free for bodily sliding adjustment within the outer member.

The spacer bars 4 prevent sliding of the channelguides during the application of the frictional grip, butmanifestly they may be omitted if the channel guides are made sufiiciently rigid.

In order to balance the pull due to the normal or initial tension desired in cables 25 and 26, the inner member is held against sliding due to this pull by a pair of heavy coiled compression springs 32, which react between the arms 2 fixed to the outer member, and the arms 1 pivotally mounted on the inner member. These springs are each shown supported around a hollow cylinder 33 which functions as a carrier for the spring and also provides a unit assembly to aid in installing the springs on the device, as the springs in their free state would be about twice as long as shown in the drawings so as to provide when compressed to the point shown the proper balancing force for the initial pull or tension of the cables desired.

In order to hold the springs in partially compressed position on their tubular supports, a col-' lar 34 is pinned at 35 through one end of the tube 33 and this collar is formed with a substantially rectangular lug 36 fitting within a similarly formed notch in the arms 2. At the opposite end of the spring is a similar collar 31, also provided with a substantially rectangular lug 38, but this collar is free to slide along the tubular support, but is stopped from coming off by means of a transversely extending pin 39 adjacent the end of the tube, the pins as previously stated all being provided with cotters or other suitable means to prevent displacement.

With the device in the form described, and assuming that it was not connected up operativel'y' ber outwardly (to the right) beyond the point where collars 31 arrived at their stop pins 30, and tnus permit easyremoval of the tubular supports as asub-assembly. However, to prevent any such sliding of the inner member and the consequent accidental dropping out of the spring assemblies from the device, suitable stops may be provided toprevent such excessiveand unnecessary movement of the inner member, but which stops may of course be removed when inspecting or cleaning the device. Such stops are here shown as U- shapedplate 40, positioned'within the right hand ends of thechannel guides and held in place as by rivets 4| and/or th anchqrafle bolts which pass through holes 4|;in the channels. This plate Ill may also iunction as a-transverse spacer or tie plate to aid ln-rigldly maintaining the channelsin theirspa'ced relation. Any other form of stop may also beused; in fact, ,a simple form ofrstop would'fbe'the' extension of pins ll into central grooves milled within the.;channel members, and which =grooves would be long enoughto-permit normal sliding action of the inner member, but prevent any excessive outward sliding action.

It is alsoldesirable, though not absolutely essential, that a pair of thin 'oover plates be ;ap-

plied to opposite sides'of the channeliframe to 1 protect the-frictional strips andleverage movemerit within from possible dirt and .dust. Such at 54 and I1, and which levers carry idler pulleys SI and 59, over which the actual operatingcables B and C extend. By this means a compounding or pulley efl'ect may be obtained, depending on the amount of turntaken by the operating cables over the pulleys 50 and 59,! thus permitting I stiffer springs 32 to be used in the controller operated by a plates are indicatedin the various drawings at by very short screws 44- ,.and at the right hand end the sections w will {necessarily be slotted as at 45 to permit movemen t of pin 9 upon which the transversely extending arms 8 are pivotally mounted. a i In practical use for aircraft cables, it has been found that a total sliding action of themembers of about from an inch and 'arhalf to two inches 40 be secured'to the channels and with lesser movement than though the controller were used in direct connection with the operating cables as shown in Figs. 8 and 9. A

hole 1. in arms 2 provides for attachment of. a lateral stay rod or wire if desired.

In Fig. 8 the controller is designated A and shown as beingdirectly connected to the operating ropes B and C which pass Over pulleys GI and. ll mounted at the ends of a rocker 82,

control rock ,shaft $3. The cables B and C pass from the rock shaft over or under any desired number of idler pulleys 64 to the control element to be rocked, and whereat they are secured in the well known manner at equidistant'points from its rocking center. y

In Fig. 9 the controller A is shown applied to the opposite ends of the cables, i. e. the pore tions adjacent the control being operated. In

this illustration the rocker 05 on the rock shaft any; desired number of guide pulleys not shown) to the cockpit of the craft for operating by the pilot in the usual manner.

In Fig; 8 the controller is shown as pivotally anchored at-a central point 69, whereas in Fig. 1

it is shown rigidly anchored at the ends oi its two channel guides.

It should be noted that while I have shown the controller as arranged to control the tension of the opposite cables of a working pair of control cables, attention is called to thefact that in some aircraft installations, instead of original adjusted position 'is maintained or not I therefore provide an indicator at 46 which slides in a groove 41 in the cover plate and indicates the mean, hot and cold position. It is of course assumed that the operating c'ables themselves, or the anchoring cables, or .rods, or both, are provided with turnbuckles, or other adjusting means for setting up the initial tension in the operating cables, and that such turn buckles or adjusting means shall be used to bring the pointer to, mid-position at mean temperature; This pointer may be secured to any portion of the inner slidable member, but in the illustration is presumed to be of the elongated form shown in Fig. 7 at 48 and apertured at 49 and 50 to fit over the ends of pins l8 and .9 respectively using a single cable at each end of a rocker a m, twin cables-are used as ment of safety. Such twin cables take the place of the single cables shown in the drawings. In

'such cases it is manifest that the twin cables may be secured to the controller in the same manner as the single cables.

Also while I show the apparatus controlling the tension in operating cables, it is evident that itwill operate in the same manner with ropes, wires, or chains, which may be used for operating movable parts of aircraft or other apparatus through the medium of rocker joints or their equivalents, and hence in my claims the word cables is intended to apply equally to suchother tension transmitting devices.

Having thus described my invention and il lustrated some of its applications to control ca-.

bles, it will be evident that many changes in detail construction may be made within the spirit of the invention and as may follow within the scope of my appended claims,

I therefore claim:

1. A tension controller for control cables comprising two adjacent members, means mounting said members for relative movement, means adapted for securing the ends of a pair of cables to one of said members, spring means interposed betweenysaid members for balancing the pull of said cables, a plurality of interleaved plates forming a normally released friction clutching means for locking said members against relative movement, and means'actuated byunan additional ele cqual pull, on said cables throwing said friction clutching means into engagement.

2. An apparatus of the character described,

provided with two parts relatively movable along I one another, the first of said parts formed and adapted for anchoring to a support, means adapted for securing a pair of cables to the second of said parts, spring means reacting between said parts balancing a pull on said cables when the pull is even and the first part anchored, and interleaved friction plate means friction'ally when the pull on the cables is greater on either one than on the other.

3. A tension controller for control cables comprisin a yoke member provided with means for the attaching of the ends of a pair of cables,

a guiding member along which said yoke member is slidable; a compression spring opposing the one-way sliding of said yoke relative to said guiding member due to tension or pull of said cables, and clutch means including a plurality of interleaved friction strips carried by said yoke member and said guide member, and means for clamping said interleaved strips together actuated by uneven pull on said cables arranged for frictionally locking said yoke against sliding.

- locking said parts against relative movement I along said guiding member, said clutch means being normally released upon the pull of the cables being balanced.

4. A tension controller for control cables comprising an outer frame memberproviding elongated guides, an inner member slidable along said guides, means adapted for securing the ends of a. pair of cables to said inner member, a pair of coiled compression springs along the outer sides of said frame member, means on said frame member engaging one end of each of the springs, and means carried by said inner member engaging the opposite ends of the springs in a' in each coiled spring provided with means coni fining the spring under some compression thereon while providing for further compression of the springs upon the relative sliding of the inner and outer members.

6. In a structure as set out in claim 4, an elon-' gated supporting and guiding member within each coiled spring provided with means confining the spring under some compression thereon while providing for further compression of the springs upon the relative sliding of the inner and outer members and stop means on said outer frame limiting the sliding movement of said yoke member in direction of releasing said springs so as always to maintain a compression thereon.

'7. A tension controller for control cables comprising an outer frame member having a pair of spaced confronting channel guides, a plurality of superimposed elongated friction strips positioned in each channel and all anchored at one' end to the channel adjacent one end thereof with a free ends extending toward the opposite end of thechannel, a yoke member slidable along the channels provided at opposite'edges with a plurality of superimposed elongated friction strips all anchored at one end thereto lying within the channels respectively and interleaved with the channel strips so as to be slidable between each other as the yoke is slid back and forth alon the channel guides, means for securing a pair of cables to said yoke for pulling the same alon the channels, compression spring means arranged in opposition to the pull o said cables, and means interposed in the attachment of said cables to said yoke operated by unequal pull on said cables for forcing said interleaved friction strips together for thereby frictionally locking said yoke against sliding during said unequal pull. v 8. A tension controller for control cables comprising an outer frame member having a pair of spaced elongated guides, an inner yoke member slidable along said guides, means for securing the ends of a pair of ables to said yokemember, a pair of coiled compression springs arranged bles and consequent rocking of said rocker for,

locking said yoke member against sliding along said guide during said unequal pull.

9. A tension controller for control cables comprising an outer frame member having a pair of spaced elongated guides-an inner yoke member slidable along said guides, means for securing the ends of a pair of cables to said yoke member, a pair of coiled compression springs arranged along the outer sides of said guides respectively, a pair of arms secured across one end of said frame member supportingone end each of said springs, apair of arms secured across said yoke member engaging the opposite ends of said springs, a rocker carried by said yoke member, means including links pivoted to the ends of said rocker for attaching the ends of a pair of cables, and means operated by unequal pull on said cables and consequent rocking of said rocker for locking said yoke member against sliding along said guide during said unequal pull, said last mentioned means including a pair of separable jaw plates adapted to be forced toward engagement with said guides respectively.

10. A tension controller for control cables comprising an outer frame member having a pair of spaced elongated guides, an inner yoke member slidable along said guides, means for securing the ends of a pair of cables to said yoke member, a pair of coiled compression springs arranged along the outer sides of said uides respectively, a pair of arms secured across one end of said frame member supporting one end each of said springs, a pair of arms secured across said yoke member engaging the opposite ends of said springs, a rocker carried by said yoke member. means including links pivoted to the ends of said rocker for attaching the ends of a pair of cables, and means operated by unequal pull on said cables and consequent rocking of said rocker for locking said yoke member against sliding along .said guide during said unequal pull, said last mentioned means including a second rocker operatively connected to said links; and a pair of separable jaw plates operated by said second rocker adapted to be forced toward engagement with said guides respectively.

frame covering said yoke and associated parts set out, a slot in one of the cover plates with indicia therealong, and a pointer projecting from said slot with its inner end connected to said 5 yoke for indicating the relative position of the same.

JOHN STURGESS. 

